Compounds and polymers containing highly fluorinated groups are widely used for providing anti-soiling and non-stick properties to surfaces. Presently, applications of fluorocarbon-type coatings require sintering at high temperature or employing undesirable casting solvents. Casting solvents currently in use are frequently costly, highly flammable, and may present potential environmental problems.
U.S. Pat. Nos. 4.592,933; 4,764,564; 4,467,836; and 4,554,325 teach using reactive monomeric surfactants in mixtures of organic/water solutions. These mixed solvent systems are useful for forming relatively thick films (greater than 1/2 mil) but suffer from two important drawbacks. First, flat films cannot be cast from these formulations since the cast liquids tend to "pull together" causing irregular surfaces. Second, thin, defect-free, glossy coating films are impossible to obtain. Clear, defect-free, glossy films are necessary for the aesthetic appeal required for automobile glazes, counter tops and other consumer uses. The coating compositions of the present invention are functionally distinguished by, among other things, their superior performance over the compositions taught in the existing art.
The present invention relates to a family of crosslinkable, anti-soiling coating compositions derived from polymeric surfactants containing pendant fluorocarbon moieties and pendant chemically reactive ionic moieties. Such surfactants are water-soluble or water-dispersible and can be thermally crosslinked with loss of charge to form tough, solvent resistant, flat, clear, glossy, low critical surface tension coatings on a variety of substrates, such as paint, plastics, metal and fabrics.